Diogo – LLM, RAG, LangChain, experts in Lemon.io

Diogo

From Canada (UTC-4)flag

AI Engineer|Senior
Machine Learning Engineer|Senior
Data Scientist|Senior

Diogo – LLM, RAG, LangChain

Diogo is a Senior AI/ML Engineer and Data Scientist with 7 years of experience across applied machine learning, LLM applications, and data engineering, backed by a strong statistics and research background (23 publications). He has built both custom transformer models and production RAG agents, a combination his technical interviewer called unusual. In his current startup role he owns the ML system end to end, and his custom models outperform frontier LLMs by over 3x on key prediction tasks, helping the company secure investment. Measurement-first and autonomous, he’s comfortable working directly with founders and CTOs.

7 years of commercial experience in
AI
Analytics
Computer science
Consulting services
Data analytics
Legal tech
Project management
Scientific research
Agentic automation
Main technologies
LLM
1 year
RAG
1 year
LangChain
1 year
Python
1 year
Machine learning
5 years
Additional skills
Vector Databases
AWS
ETL
SQL
PostgreSQL
OpenAI
Plotly
Airflow
Data Science
R
LangGraph
AI agent development
AI chatbot development
AI API integration
AI deployment
LLM orchestration
Hugging Face
Business intelligence
Amazon EC2
Amazon S3
Data visualization
Direct hire
Possible
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Experience Highlights

Senior Machine Learning Engineer / AI Engineer
Feb 2026 - Ongoing7 months
Project Overview

A legal tech platform that predicts how a court case is likely to unfold. General-purpose LLMs couldn’t reliably forecast this, and they performed no better than an informed guess. The platform models each case’s event history together with structured context such as jurisdiction and case subject. It uses this to forecast next events and likely outcomes for legal professionals. Its models are trained on a historical dataset of 30M+ case records.

Responsibilities:
  • Leads end-to-end development of the platform’s ML system. Builds custom transformer models that outperform frontier LLMs by over 3x on key legal prediction tasks, results that helped the company secure multi-million investment.
  • Designed the modeling approach through measured iterations: from prompting frontier LLMs, to fine-tuning open models with QLoRA, to a BERT-based classifier that embeds jurisdiction and case subject as categorical features alongside case event history.
  • Set up entropy-based baselines and leakage controls (case-wise data splits, temporal masking of future events) so reported gains reflect real predictive power.
  • Builds reproducible training and evaluation pipelines with PyTorch, Hugging Face, MLflow and Docker, and hands off production-ready models for deployment.
  • Runs EDA and ETL over 30M+ rows using SQL and Ray to prepare training data.
  • Guides supporting contributors and reports progress to leadership through weekly executive summaries.
Project Tech stack:
Python
PyTorch
AI API integration
Cloud Computing
Docker
LLM
LLM benchmarks
LLM evaluation
Neural Networks
MLflow
SQL
ETL
Ray
Senior Data Scientist / AI Engineer
Jul 2024 - Feb 20261 year 7 months
Project Overview

A job market intelligence platform that turns large volumes of job postings data into insights for analysts and business stakeholders. It replaces manual data labeling and ad hoc analysis. New job market records are ingested and classified every month and stored in a data warehouse. Stakeholders explore the data through interactive dashboards and a conversational AI assistant that answers questions in plain language. The database holds 100K+ records and grows by 1,500+ records monthly.

Responsibilities:
  • Built and deployed a chat-based AI agent with LangChain, RAG, Milvus and PostgreSQL that lets stakeholders query a 100K+ row job market database in plain language, cutting time to insight by over 30%.
  • Built a generative AI data labeling tool on LLM APIs (OpenAI) and Haystack that classifies records with 86% accuracy, saving 300+ working hours per month.
  • Designed and deployed an ETL pipeline with Python, Airflow and AWS (EC2, S3) that automates ingestion into the data warehouse, adding 1,500+ new records monthly.
  • Traced and evaluated LLM pipelines with LangSmith.
  • Developed a predictive modeling app and Metabase dashboards with Plotly visualizations for stakeholder reporting.
Project Tech stack:
Python
Airflow
AWS
ETL
OpenAI
LLM
RAG
Vector Databases
PostgreSQL
LangChain
SQL
Plotly
LLM evaluation
AI agent development
AI API integration
AI system design
Data Scientist / AI Engineer
Jan 2021 - Jul 20243 years 5 months
Project Overview

A SaaS platform that generates analytical performance reports for content creators. Before it, a report took around two months to prepare manually. The platform collects creators’ data into a managed database and runs machine learning and generative AI analysis over it. It then delivers a ready-to-read report with visualizations.

Responsibilities:
  • Built the SaaS end to end, automating analytical report generation and cutting delivery time from 60 days to 5 minutes.
  • Designed the database and backend with Supabase and FastAPI.
  • Integrated LLM APIs and machine learning models to generate the report’s analysis and insights.
  • Built the visualization layer and deployed the application to the cloud.
Project Tech stack:
Python
SQL
Machine learning
LLM
ETL
Cloud Computing
FastAPI
AI API integration
Supabase
Design system
Database design
Data Scientist / Scientific Researcher
Feb 2019 - Apr 20223 years 2 months
Project Overview

Psychometric assessments developed in a university research lab to measure different dimensions of human behavior. The lab designs new tests, validates them statistically on participant data, and publishes the findings in peer-reviewed journals.

Responsibilities:
  • Co-developed and validated 3 original psychological tests using advanced statistical modeling and machine learning in R.
  • Contributed to 23 peer-reviewed scientific publications.
  • Processed and visualized research data to support test validation and publication.
Project Tech stack:
Data Science
Machine learning
R
Data visualization

Education

2024
Computer Science
Applied Data Science and Big Data Program

Languages

Portuguese
Advanced
French
Advanced
Spanish
Intermediate
English
Advanced

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